Amino-labelling compounds

Does anybody know of a company which will add an amino acid tag onto a small organic compound? I am working with a small commercially available molecule, cyclosporin. A previous collaborator was able to attach an alanine onto the cyclosporin. This enabled us to immobilize the compound on an affinity matrix and pull down interacting partners. However, we have very limited quantities of the Alanine-labelled cyclosporin left and Im wondering is there any company that provides this type of service.